Gonzo
Thats why Captains get paid all that money...to make a decision at the time. Probably good job we all don't make the same one.
Worrying about the second runway (or both) closing seems a bit pointless when if you had diverted to LGW the single runway could be blocked on arrival.
JAR-OPS gives us flexibility to make a valued judgement based on individual circumstances and experience. Long may it continue.